D-Link DES-3326SR User Manual page 138

DES-3326SR Layer 3 Fast Ethernet Switch User's Guide
Link-State Update packets are multicast on those physical
networks that support multicast/broadcast. In order to make
the flooding procedure reliable, flooded advertisements are
acknowledged in Link-State Acknowledgment packets.
retransmission of certain advertisements is necessary, the
retransmitted advertisements are always carried by unicast
Link-State Update packets.
The format of the Link-State Update packet is shown below:
Link-State Update Packet
4
Version No.
Checksum
Number of Advertisem
Link-State Advertisem
Figure 5-26. Link-State Update Packet
The body of the Link-State Update packet consists of a list of
link-state advertisements. Each advertisement begins with a
common 20-byte header, the link-state advertisement header.
Otherwise, the format of each of the five types of link-state
advertisements is different.
Packet Length
Router ID
Area ID
Authentication Type
Authentication
Authentication
ents
ents ...
126
If